Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 81)

Memory concept
4.2 Memory functions
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
4-19
4.2.7 Backup of project data to a Micro Memory Card (MMC)
Function principle
Using the Save project to Memory Card and Fetch project from Memory Card functions, you
can save all project data to a SIMATIC Micro Memory Card, and retrieve these at a later
time. For this operation, the SIMATIC Micro Memory Card can be located in a CPU or in the
MMC adapter of a PG or PC.
Project data are compressed before they are saved to a SIMATIC Micro Memory Card, and
uncompressed when fetched.
Note
In addition to project data, you may also have to store your user data on the MMC. You
should therefore first verify MMC memory space.
A message warns you if the memory capacity on your MMC is insufficient.
The volume of project data to be saved corresponds with the size of the project's archive file.
Note
For technical reasons, you can only transfer the entire contents (user program and project
data) using the Save project to memory card action.